| I will entertain all reasonable offers on these. Here are a pair of late 50s BA-21-B germanium transistor microphone pre amps from a General Electric 4-BC-21 recording console. These are great sounding units, the germanium transistors were developed to mimic the sound or tubes and because of that these have a very fat sound with a lot of punch. These are great for vocals, guitars, and drums they are very hi-fi, quiet and very musical. They have a two position pad on the front for -30 and -50dB, this pad is only on the B version of these and can be easily disconnected if preferred. These came from a working console but have been in storage for 15 years so they will probably need new caps. I will include a PDF of the 4-BC-21 manual that includes schmatics and all requirements for the pre amps. These need an external power supply of 25 volts DC so they have a lot of head room. Sold as is as described.